The demands from the motor do not remain... because the volts drop and thus the motor can't drive as hard anymore anyway. Amps drop too then of course. Amps are a RESULTANT of Volts over Impedance (the motors).... not something a motor has any fixed need for. It is a Dynamic thing... not fixed.
I guess you effectively get a "Capacity Remaining x C" result, but it might not be truly that relationship.

All that really matters is that better batteries (Higher C) can maintain higher volts longer, thus the motor draws more Amps, and the battery can still provide those. Whilst a lower C drops off more in volts, thus less Amps/Power... AND its construction is less efficient and temps get worse than for a higher C, thus it can end up in detrimental areas of operation, whist the higher C never did.

To prevent that in a lower C, you just can't use the capacity to as low a level as the higher C.
eg 5000 30C, only use to 70% - not the commonly quoted 80%.
In reality all that matters is the HEAT... so "80%" is just a bandied about generalisation. You can use MORE, or might need to use LESS... that is set by the HEAT you reach. If it comes down cool then you could have used more capacity. And vice-versa.... comes down hot, use LESS in future.

why do you think I posted the video links with the various batteries and there C rating. It was to show that the big difference in performance was anecdotal. What appears to be a big improvement was some what not noticable or just near a tipping point of 1:1. You look at all the videos and they all look fantastic for pretty much the first half of the flight. The lower C or lower mAh batteries start slowing down earlier, fly bys fan wine is less because the drop off is already occuring. High C rated, they push all the way near to the end, but they don't significantly out perform the others. They do but just ever so slightly. If you get a High C heavy battery, with is why I added the weights to and did it weight order, you see the the higher C can be undone by the higher weight.
That's why I keep advising, it depends on how you intend to fly. And its also why I have the 35C5800 and the 55C5500 and 50C5000. It becomes how long do I want to push hard for this flight vs I just want to go mixed throttle for longer.

Quote:

Originally Posted by PeterVRC

But.... the Su will fly "OK" on the 30C's (mind you mine are HET2W30s in CS10s - more demand than stock). "OK" meaning nothing amazing, and quite different to the 65C Nanos.

From all the other various battery Cells, C's, Capacities, I have.... I see the 25C Nanos are towards a 30C, maybe 35C, non Nano type battery. Certainly no more than that.
And the 35C Nano's are clearly better than the 25C ones (I have a few capacities in 4S of both).... it is like the 25C's were the 'rejects' of the Nano family. They fly with less power, and get much hotter - even puff if not careful - than the 35C versions of them.

Whether a $110 65C is better than a $70 30C, in your own use/application, is up to your assessment - but it certainly won't be anywhere near the same performance - from start to finish. And as long as the 30C isn't driven to be overly hot (via high current demand OR large capacity depletion) that is acceptable.

Holly... This page has been dedicated to the PeteVRC Maxthrottle Exchange. Thank you all our views, and have a good night

Quote:

Originally Posted by PeterVRC

....All that really matters is that better batteries (Higher C) can maintain higher volts longer, [AGREED and using your number only .7V more]thus the motor draws more Amps,[AGREED but with only .7V more to the motor the Amps isn't going to be marginally higher] and the battery can still provide those [yes they all can, only as capacilty depletes the higher remains above demand longer where as the lower starts this shallow drop off sooner]. Whilst a lower C drops off more in volts[MORE in volts? theres only a .7V difference], thus less Amps/Power [AGREED]... AND its construction is less efficient and temps get worse than for a higher C, thus it can end up in detrimental areas of operation, whist the higher C never did [WELL not true because again this is chemistry. The Peak number range differs with each recipe and the level of integrity depends on the peak number in a 10 sec burst].

To prevent that in a lower C, you just can't use the capacity to as low a level as the higher C.
eg 5000 30C, only use to 70% - not the commonly quoted 80%.[Again see above the integrity is where the peak number comes in]
In reality all that matters is the HEAT... so "80%" is just a bandied about generalisation [Agreed]. You can use MORE, or might need to use LESS... that is set by the HEAT you reach. If it comes down cool then you could have used more capacity. And vice-versa.... comes down hot, use LESS in future [Not true. Capacity is capacity. There can be many other factors to the recipe that dictates how hot a battery comes down but temp to is a loose indicator].

Dude what time is it where you are. I though i was up late! Again I generally agree with you but its not as great a difference as some may perceive but when and low C rating starts to drop off below demand is easily and clearly visible and it happens earlier than many low C fliers realize cutting into the peak rating heating or changing the composition of their lipos. Thus they fail sooner when repeatedly abused.
The part I still haven't figured out is why High C rated batteries are more sensitive to failing to store them at 50%-70% charge. I've been asking my bro who test cells, Hydrogen, Lipo etc for Canadian ratings standards for Hybrid cars and such. He still hasn't given me a useful answer.

In high demand situations (EDF itself + higher ends of that) things get notably worse with batteries. My Su is 110A area WOT, which the 5800 30C are not too impressed with doing! Flights have to be dramatically less WOT time, and total flight time, than for 65C. Plus WOT results are not as strong.

In high demand situations (EDF itself + higher ends of that) things get notably worse with batteries. My Su is 110A area WOT, which the 5800 30C are not too impressed with doing! Flights have to be dramatically less WOT time, and total flight time, than for 65C. Plus WOT results are not as strong.

3:30pm I keep forgetting your in your next day.
Still don't know how you manage to get a 110amp demand but absolutely. The 5800 could only deliver 110 amps for the first 2000mAh. After that is would progressively drop in deliverable amps. The Voltage drop curve is very different than the Delivered amp drop off. And the Voltage drop varies brand to brand.
As I've said I've purchase batches of batteries and some have a 1 or 2V drop under load while others of the same battery Brand capacity and C drop off even more. It all comes down to was you cell made from the top of the pot or the bottom. Did they stir it less and mine got more of the magical leprechauningredient on not. Expensive batteries tend to test and balance cells. Cheaper one have less testing.
Its for these reasons, why the ratings and the differences are marginal and takes more a wait and see how other confirm how a battery performs. Its why Genesis, GenAce and Hyperion tend to lead the pack..... and then there is MaxAmps. All the same ratings but even better numbers because it varies with batch chemistry.

Two Lander CS10 tests. 5800mAH 30C and 5000mAh 65C
Pretty much the exact same resulting combos as my HET2W30/CS10's in the Su.
Basically 100W, and 100g thrust, difference between them over a typical general power period (WOT). But also later in the flight the 5800 30C is really under duress, whilst the Nano is happy all flight. 5800 comes down 'hot', Nano 'warm'. $108 versus $70.... probably a linear result of operation versus dollar really. Lifespans... yet to be seen....

The HET2W30 test below (third in the list) was done on a PAIR of 4000mAh 30C, to give more current ability to it so as to find out better what its max would really be with a good battery (eg 65C). But it is still only "240Amp capable", versus a 5000mAH 65c being "325Amp capable" and lower IR also.
I hadn't done a bench test with 65C and didn't want to pull them out of the Su again just for that... one day I will. But they are extremely similar to the Lander anyway, so those numbers are a good reference.
But note how those 30C's go sub-22v immediately! The 65C can stay over for quite a while. Because the IR total of either case has the 65C the winner of being the lowest - which is the main thing that you pay for in a Nano.

Neither the HET2W30, nor Lander2960, like 70Amps+ of WOT for very long! Alloy housings and great cooling or not! But you wouldn't (shouldn't?) need WOT sustained for too long ever anyway. So the battery and motors get to cool off in between those times anyway (hopefully!).

Oh yeah.... 70+ Amps EACH on the bench.
But of course much less in-plane. I don't remember if I actually tested/video'd in-plane.
I don't recall ever seeing over 110Amps... but maybe it was. I wouldn't think it could ever go over 120Amps area... even at initial peak. I use 90A ESCs.
The Su ducting (exhaust) limits CS10's (chokes them) so they can't get to max power ever anyway. But every 1mm more exhaust diameter you can get helps some measurable amount - it would probably need 3mm to 4mm more diameter to free them fully? I am not sure exactly.

Pete; I hope you're not basing anything on 14 seconds 65C demo. You didn't even run it long enough to settle in. I don't get the comment hot and a lot of power... even for the very short 14 sec it still only was around 22 V. So some how you can run at 21V for almost a minute but not at 22V for more than 14 sec?

And the 30C5800 isn't in distress.... that's just a normal run. It was about 1V+ lower and the amps dropped off from about 73 -70amps. all expected but then the Voltage stayed around 21V for the duration. If you run them longer you'll see the voltage fal off doesn't match the amp fall off. But its a cheaper lower quality battery so the fall off differs.

If you're concerned about cooling point a fan at it and run it. Its meaningless unless you run them under the same conditions and monitor after the first 45 seconds to a minute.

I guess I'm now officially a member of your club, as I just purchased one of these puppies from BananaHobby. I opted for the desert camo color scheme, ARF version, should be here in about a week. Haven't bought batteries or anything else yet, I'll wait until the plane gets here first.

It's Winter here in Wisconsin, so I won't be flying for a while, but it will give me time to read this entire thread from the beginning. The info and tips contained in here will no doubt be invaluable...................

I have a 2.4 Ghz 7C Futaba radio that I had planned to use in it, but does anyone have any experience with the Sky Flight 12Ch radio that BH has for sale?? $80 for Tx and Rx is a hard price to beat!! Does it have any programmable mixes (flaperon, ailevator), end point and travel volume adjustments, etc. etc.?? No sense messing with it if it doesn't at least have the basic functions that this airframe will require..........

I guess I'm now officially a member of your club, as I just purchased one of these puppies from BananaHobby. I opted for the desert camo color scheme, ARF version, should be here in about a week. Haven't bought batteries or anything else yet, I'll wait until the plane gets here first.

It's Winter here in Wisconsin, so I won't be flying for a while, but it will give me time to read this entire thread from the beginning. The info and tips contained in here will no doubt be invaluable...................

That was because I have run them longer and I KNOW they get very hot. (motors). Maybe they will last doing that, but I don't risk it. Demag one to find out....
So does the 30C battery, but not the 65C much at all.
So once I know something detrimental occurs I don't do that again!
The short runs show what WOT runs will do. Give it a short rest, WOT again, and it will get near peak again.... not for long though!
The bit longer ones show what it falls to as a more realistic value you will get to use.
And nothing to do with what occurs later in runs, the tests are not aimed to show that at all. On the bench is not a lot of use for that so I test that in flights and work it out... starting short (2mins or so).

Then do a lower apple with apple comparison.
Run them all at 50 amps for longer and watch the voltage across them as well as the drop off with the same motor/fan.
Oh and document the result over the same time. You'd also need state the charge in condition of each battery tested to show them starting from nominal potential.
Either way we are in agreement with maybe the margin of improvement one over the other. There is a margin particularly at the start but [not] a significant one.